This invention relates to field effect transistors (FETs) and, more particularly, to Group III-V compound FETs.
Optoelectronic devices based on the Group III-V compound materials systems have become the building blocks of long wavelength optical communication systems. These devices include lasers, light emitting diodes, photodetectors, field effect transistors (FETs), and integrated combinations such as FET-photodetectors. Hence, the design of high performance InP and/or InGaAs-based FETs has become an attractive target of research; InGaAs because of its high mobility and InP becasue of its high peak and saturation velocities of electrons. In addition, InP has favorable MIS (metal-insulator-semiconductor) interfacial properties which allow the formation of n-channel inversion or accumulation layers on semi-insulating InP. On the other hand, active research and development is also apparent in GaAs/AlGaAs materials both from the standpoint of integrating electronic circuits as well as integrating optoelectronic devices with electronic circuits.